1. Field of the Invention
This invention relates to an exfoliating device for a synthetic resin cover layer of a cable.
2. Description of Related Art
An assembly of conductors with insulator layers provided thereon or optical fibers which have a common cover layer provided thereon is commonly called cable. Cables for communications are roughly divided into a land cable and a submarine cable, but either of such cables commonly has a synthetic resin cover layer provided as an outermost layer thereon. Since an optical submarine cable transmission system using, for example, an optical submarine cable is superior in prevention of noises and in delay time and can assure maintenance of secrecy comparing with transmission quality of radio communications based on a communications satellite or conventional short waves, it is employed widely as international as well as domestic communications means. In order to connect such a cable as an optical submarine cable to a relay or the like, it is necessary to exfoliate all cover layers at a terminal end portion of the cable to expose a core of the cable. Since such an exfoliating operation is normally done at a site where the cable is to be installed in a bad operating situation, it is demanded for the exfoliating operation to be high in operability.
An exemplary one of conventional methods of exfoliating a synthetic resin cover layer of a cable is illustrated in FIG. 1. In particular, a blade of a knife 3 is held to a synthetic resin cover layer 2 of an optical submarine cable 1 and then drawn by a predetermined distance in a direction of an axis of the cable 1 whereafter the cover layer 2 is exfoliated from a core. Such a method as illustrated in FIG. 2 is also employed conventionally. As seen in FIG. 2, a dedicated plane 4 having knobs provided at the opposite ends thereof is used, and the plane 4 is gripped by the opposite hands of an operator and held to a cover layer 2 of a cable 1 and drawn forwardly to shave the cover layer 2.
However, the exfoliating method illustrated in FIG. 1 has drawbacks that it is difficult to maintain the holding force of the knife 3 fixed and since the depth of the cut may vary, a cutting operation may have to be repeated several times and that a layer under the cover layer 2 to be exfoliated may sometimes be damaged. Further, when the cover layer 2 is hard or thick, the blade of the knife 3 may not cut into the cover layer 2 and it is difficult to exfoliate the cover layer 2.
On the other hand, with the conventional method illustrated in FIG. 2, since the cover layer 2 is shaved by the plane 2, the plane 2 must be operated several times to shave the cover layer 2 until the cover layer 2 is exfoliated. Accordingly, there is a problem that a long period of time is required until the cover layer 2 is exfoliated. Further, even if the cable 1 is fixed, it still moves a little, and when the cover layer 2 is shaved by a great distance, the cable 1 often becomes uneven or is brought out of a straightened or flattened condition. Also, since biting of the blade of the plane 4 into the cover layer 2 is not fixed, the cover layer 2 cannot be shaved into a fixed thickness, and there is a possibility that the plane 4 may be let off from the cable 1 and the operator may be hurt by the plane 4.
Accordingly, it is an object of the present invention to provide an exfoliating device for a synthetic resin cover layer of a cable by which, overcoming the drawbacks of the conventional methods described above, an exfoliating operation of a synthetic resin cover layer of a cable can be carried out in safety and with certainty and the synthetic resin cover layer can be exfoliated in a short period of time.